Magnetic

In maritime navigation, magnetic refers to any direction or bearing measured relative to magnetic north, the direction indicated by a magnetic compass. A magnetic heading, course, or bearing differs from a true direction because magnetic north is not the geographic North Pole, and because vessel-specific magnetic influences can alter compass readings.

Understanding magnetic references matters when steering, plotting a course, or comparing instruments. The Compass may show magnetic, while a GPS or Chartplotter can display true or magnetic depending on settings. Converting correctly helps maintain an accurate heading, avoid off-track errors, and keep navigation consistent in poor visibility or offshore.

In PredictWind, check whether connected instruments and chart displays are using true or magnetic directions before comparing them with forecasts or routes. The DataHub can receive heading and GPS data from onboard networks, so keeping compass calibration, deviation tables, and display settings aligned supports cleaner logs, tracking, and routing decisions.